1. Field of the Invention
The present invention relates to a facsimile machine and more particularly to a facsimile machine including a retrieval unit for retrieving data of an image from a document, an encoder for encoding the retrieved data, and a memory for storing the encoded data when the encoded data is not to be immediately facsimile transmitted.
2. Description of the Related Art
Generally facsimile machines are capable of two types of transmission. With the first type, the facsimile machine transmits encoded data immediately to a remote device. In the second type of transmission, the facsimile machine stores encoded data in a memory and transmits it at a later time. This first type of the facsimile transmission is called direct transmission and the second type of transmission is called memory transmission.
Conventional facsimile machines are provided with a retrieval buffer memory and an independent transmission buffer memory. Image data retrieved from a document by a retrieval unit is stored temporarily in the retrieval buffer memory before being encoded by an encoder. When the encoded data is to be facsimile transmitted, the encoded data is temporarily stored in the transmission buffer memory. The retrieval buffer memory and the transmission buffer memory are separate units used independently during direct transmission and memory transmission.
However, retrieval processes for retrieving image data from a document are performed faster than encoding processes. As a result, while the image data is encoded by the encoder during memory transmission, if the memory capacity of the retrieval buffer memory is too small, then the image data retrieved by the retrieval unit at a quicker rate quickly fills empty space in the retrieval buffer memory. This can result in termination of retrieval operations, so that time required to retrieve a document's image increases. Although, such a problem can be overcome by increasing the memory capacity of the retrieval buffer memory, this requires provision of a large capacity RAM, which would increase production costs.